john deere 854 round baler help

[the baler]

just newly aquired j.d.854 silage special, am having real hard time getting the unit into the field, im new to the bale trak system, seems very complicated. upon making the first bale the twine arm wont activate automatically even though its in twine mode, i get a twine bale flashing on the upper left and a net bale flashing under the top icon on the upper right, also after the fact of baling a few bales with no twine i unplugged the twine arm solenoid and replugged it and the arm retracted to the furthest position and upon extending it, its hitting what appears to be a knife or holder of sort, it would seem that f the knife retracted up that it would have the clearance to extend fully, also noticed some slight differences in a diagram in the op. manual, which is nearly 400 pages, my unit had the twine pulleys directly centered on one another were as the book shows them offset so the twine routs dont interfere with one another, also the book shows sensors behind the pulleys, mine dosnt have these and there are no sighns that they were ever there, no wear marks at all, i havent even attempted to use net yet. any help from someone familiar with this particular unit would help a fellow farmer tremendously, thanks